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Diggester sends this quote from an article at the BBC:
"The ID24 beam line at the European Synchrotron Radiation Facility will use X-ray beams to subject iron and other materials to extraordinary temperatures and pressures. How the X-rays are absorbed should give insight into the mysterious processes going on at and near the Earth's core. For example, the work could unravel why the Earth's magnetic field can 'flip.' ... The samples are compressed at a pressure millions of times higher than that on the Earth's surface. High-power lasers are then fired through the diamonds at the samples, heating them to higher than 10,000C. Then X-rays are used as a probe to determine the precise composition and chemistry of samples."

The summary makes its seem like they're using the X-rays to do the heating and compressing when in reality the material is compressed in a diamond anvil cell. The X-rays are used to study how the material changes under heat and pressure. The original article makes the same mistake.

The X-rays will certainly heat the sample very rapidly indeed, and thereby probably increase the pressure in the cell, at least briefly, so I don't think the article is all wrong. Probably better to think of the diamond anvil cell as a pre-pressurizing step.

Only in science fiction, stevelinton. Doctor Morbius is correct. The power in the monochromatic X-ray beam at ID24 is less than a Watt. Only powerful enough to heat your imagination. All the pressure is provided by the diamond anvil cell. The experimental technique, X-ray diffraction, is used to characterize the crystal structure of a sample under carefully controlled conditions. This same type of high-pressure environmental science experiment is done at the Advanced Photon Source (USA) at beam lines

Core temperature is driven by pressure from the gravitational attraction of every atom on and around Earth. This causes enough heating to make the mantle to become liquid. The mantle itself is liquid sodium which conducts electricity. The core itself is mostly iron/nickel and is under such high pressure it remains a solid (Clausius Clapeyron relation [wikipedia.org]

At the Earth's core, pressure is around 330 - 360 gigapascals [wikipedia.org], 330 million times atmospheric pressure.Deep Water accident was only 120,000 times atmospheric pressure. There isn't any danger of the core cooling down.

The effect of convection currents and the Earth's spin forces the liquid mantle to start rotating which in turn causes magnetic fields to form. This was the subject of a scientific experiment [inria.fr].

The idea is that these individual rotating eddies can at times reinforce each other to form a strong dipole system as we have now, and at other times cancel out or form a weak multipole system, which would last until a new strong dipole system formed.

There are other theories that different layers of the Earth rotate at different speeds, having other electromagnetic effects on the Earth.